Morphological criteria to identify faecal pellets of sympatric ungulates in West African savanna and estimates of associated error

Abstract

Indirect surveys may prove to be useful tools in complementing classical direct counts when monitoring ungulate populations and may also promote better understanding of the precise structure and functioning of the rich ungulate communities of African savannas. However, the identification of faecal pellets can be difficult where several sympatric species occur. This study develops simple field criteria for distinguishing between pellets among ten sympatric West African ungulates. A discriminant analysis was performed, using the mean of measurements of pellet groups from different species to pinpoint and characterize the most useful morphological criteria for separation between them. The mean diameter of pellets within each pellet group proved to be the most valuable variable for species segregation, whilst the second axis separated species by mean indent depth. The pellet groups of six of the ten designated species could be identified with a minimum misclassification error. However, no simple morphological variables emerged to permit discrimination between hartebeest and topi, or between bushbuck and Bohor reedbuck pellets. Once pellet groups have been identified, their density and spatial distribution may provide useful information on the use of space and habitat of sympatric species, over given periods.

Low accuracy of identifying Neotropical deer species by scat morphology

“…Our results contradict the idea that diet has a strong influence on scat shape and size (Chame 2003) and the observation by Hibert et al (2008) that captive samples show important differences from wild African ungulates. However, these characteristics have only now been tested directly on species of Neotropical ungulates, so drawing definitive conclusions about how much influence diet may have is premature.…”

The use of non-invasive molecular techniques to confirm the presence of mountain bongo Tragelaphus eurycerus isaaci populations in Kenya and preliminary inference of their mitochondrial genetic variation

“…Despite this, these error rates are similar to those reported by Bowkett et al (2009), using dung morphology to differentiate antelope species in the Udzungwa Mountains of Tanzania. Hibert et al (2008) also experienced difficulty discriminating dung pellets of some sympatric antelope species from West African savannas; four out of ten species analyzed could not be distinguished by morphological measurements. Our results illustrate the importance of incorporating molecular methods into faecal-count studies, especially to aid species identification.…”

“…Methodologies based on faecal counts are commonly used, though there are many possible errors associated with these methods (Neff 1968) such as variable defecation rates, unknown decaying times and difficulty in identifying pellets of sympatric species (van Vliet et al 2008a, b). Discriminant analysis of morphometric measurements of pellets from ten sympatric West African ungulates has demonstrated that only six species could be correctly identified in the field (Hibert et al 2008). The reliability of pellet count methodologies can be improved by association with other techniques, such as direct observation, radio-tracking and molecular approaches.…”

Deforestation and cattle ranching drive rapid range expansion of capybara in the Gran Chaco ecosystem

“…Fecal samples were collected during surveys for subsequent DNA analysis. Pellet size varies among age class and sex (Murphy et al, 2003;Wehausen et al, 2004;Hibert et al, 2008;McCann et al, 2008) therefore, we avoided resampling the same individual by collecting different sized pellets at discrete water features within a population. In total, we collected 110 samples from 13 sampled populations (Fig.…”